This invention relates to an electrical connector which is able to be mounted on a circuit board of an electrical appliance with great stability maintained for a long time.
With electrical or electronic appliances, for example, as shown in FIGS. 6 and 7, one connector body 20 of an electrical connector 10 is often mounted on a circuit board 1 arranged in an electrical appliance in a manner such that a mating connector socket 21a forming part of the shell 21 of the connector body 20 as its outer casing is positioned in a connector opening 2a formed in a panel plate 2 as part of a casing of the electrical appliance, thereby enabling a mating connector (plug) 30 to be inserted into the mating connector socket 21a of the shell 21.
The connector body 20 is a resin-molded body having contacts arranged in its inside. The shell 21 forming the outer casing of the connector body 20 is a worked body made of a metallic plate, for example, a copper plate coated with nickel plating or solder layer, which is worked by punching and bending processes. The shell 21 is formed with fixing legs 22 extending from its bottom surface as shown in FIG. 8. In mounting the shell 21 onto the circuit board 1, the fixing legs 22 of the shell 21 and protruding terminal legs 40 of the contacts are inserted into predetermined fixing apertures (through-holes) and fixed thereat by soldering as shown in FIG. 7.
Such a soldering can simply be performed, for example, by moving along the surface of molten solder in a bath the circuit board 1 having the connector body 20 temporarily fixed thereto. This soldering method is effective owing to its high productivity and ensures the reliable fixation of a connector body 20 to the circuit board 1 substantially with a sufficient strength.
Therefore, even if the shell 21 of the connector body 20 is only positioned in and spaced from the connector opening 2a of the panel plate 2, no troubles occur in use, so long as the mating connector 30 is accurately inserted into the socket 21a of the shell 21 taking particular precautions.
However, problems will arise with any inaccurate insertion of the mating connector 30 into the socket 21a, for example, in oblique directions misaligned with the correct insertion axis in every direction, or mishandling insertion. With such cases, the shell 21 would be subjected to great loads (stresses).
When the shell 21 is subjected to such loads, the shell itself tends to deform so that the rectangular shape of the shell is distorted or the fixing legs 22 of the shell 21 are deformed and, in extreme cases, are broken. Once such deformations or distortions have occurred, they make it more difficult to insert the mating connector into the shell 21 and forced insertions are unavoidably repeated due to the difficulty of insertion, finally resulting into exchange of the connector body 20 itself for new one or even together with the circuit board.
In general, the shell 21 is a worked body made of a metallic plate which is worked by punching and bending processes as described above and is simply arranged over the outside of the resin-molded connector body 20 as by press-fitting. Therefore, on being subjected to undue forces thereon, the close contact between the shell 21 and the connector body 20 may be adversely affected and shell 21 itself may be deformed.
Particularly, with the shell 21 as shown in FIG. 8 having the mating connector socket 21a formed as a frame structure 23 in the form of a container by folding the metallic plate, including butt faces 23a at a center of the bottom surface, on being subjected to the undue forces the butt faces 23a abutting against each other will tend to open or separate from each other in many cases.
When the butt faces 23a of the frame structure 23 are opened or separated, the shielding effect of the shell itself and the grounding effect disappear and cause troubles such as delicate change in characteristics of the connector body 20. Moreover, the separation of the butt faces 23a of the frame structure 23 causes the mating connector socket 21a to widen or enlarge so that the mating connector 30 inserted in the socket 21a l becomes likely to be dislodged therefrom.
If the undue force acting upon the shell 21 cannot be sufficiently supported by it, great stresses are caused in the protruding terminal legs 40 of the contacts and the circuit board 1. As a result, there is a risk of failures such as cracks and peelings in printed circuits on the circuit board, connections between the connector body and the contacts, and other locations, which may finally cause malfunctionings and troubles of the appliance itself.